Is Gastric Bypass a Cure?

I've heard that people who have gastric bypass surgery "lose" their diabetes almost immediately. I've also heard that many of those who have had gastric bypass regain some of their weight after a while. When this happens, does the diabetes reoccur?
Name Withheld

Robert Gabbay, MD, PhD, responds: Gastric bypass helps some people with type 2 diabetes in a number of ways. Clearly, the profound weight loss that many people experience after this kind of surgery helps their diabetes by improving blood glucose, cholesterol, and blood pressure. What is interesting is that some of the benefits—in particular, the improvement in blood glucose control—happen very quickly after the surgery, before much weight loss has occurred. It is believed that by bypassing some of the intestine, hormones from the gut are changed, improving the body's ability to make insulin. After gastric bypass surgery, many people have been able to—in consultation with their health care providers—stop some of their diabetes medications. Some people are even able to stop all diabetes medications. In some ways, this might be called a "cure," but in other ways, we are not sure yet.

Health care providers often consider that the diabetes these people have—the people who are able to stop taking diabetes medications after surgery—is being controlled through weight loss. But the reason it is important to not consider this a true "cure" is that these people still need to be periodically evaluated for diabetes complications. Despite stopping diabetes medications, people who have undergone gastric bypass should still continue their screenings and preventive measures, including having their eyes examined annually and having their urine checked for protein and kidney disease. Some people do regain some of the weight lost after surgery, and for them, the need for medications to treat their diabetes often returns.